Engorgement during pregnancy

Hello! I am 26 weeks pregnant with my second child. I had continued breastfeeding my first until I was around 16 weeks when my milk dried up. Yesterday I noticed my breasts were really heavy and almost full feeling but chalked it down to normal breast pain in pregnancy. When I woke up this morning both breasts were full and rock hard. My left one is so sore to the touch and has been leaking all morning. Has this happened to anyone else before? Should I be concerned? Also any tips on dealing with the full feeling would be greatly appreciated